[1] Chinese Acad Sci, Inst Automat, Beijing 100049, Peoples R China
[2] Univ London, Dept Comp Sci & Informat Syst, London WC1E 7HX, England
[3] Univ Maryland, Dept Elect & Comp Engn, College Pk, MD 20742 USA
[4] Univ Texas Austin, Dept Elect & Comp Engn, Austin, TX 78712 USA